A number of personal care products, which are directed toward improving the health and physical appearance of keratinous tissues such as the skin, hair, and nails, currently are available to consumers. There exists a continuing need, however, to regulate the condition of keratinous tissue by delaying, minimizing or even eliminating skin wrinkling and histological changes typically associated with the aging of skin or environmental damage to human skin. In addition, there exists a need for cosmetic agents to prevent, retard, and/or treat uneven skin tone by acting as a skin lightening or pigmentation reduction cosmetic agent.